Animal viruses have been proven to be oncogenic in unnatural hosts. In fact, viruses benign in the original animal reservoir may be oncogenic when transferred to other species. Man might be one of these species. Veterinarians are exposed occupationally to sick animals and have been infected by such exposures. If animal viurses are oncogenic for man, these professionals may have an increased risk of cancer, especially specific types such as leukemia, lymphoma, or others. The mortality of graduates of eight veterinary schools will be ascertained through alumni records, directories of the American Veterinary Medical Association, and obituary notices. Cohort and calendar time death rates as determined by life-table analysis will be compared to the rates for U.S. white males and physician specialists. The site-specific cancer mortality rates may indicate a risk from animal virus exposure.